Alignment systems for GlueX
description
Transcript of Alignment systems for GlueX
Alignment systems for GlueX
GlueX Collaboration Meeting
Bloomington, Indiana
May 20-22, 2004
Courtesy of Dimos Sampsonidis, Aristotle University of Thessaloniki
Presented by Zisis Papandreou, University of Regina
NIKHEF Web Page
Pattern used to measure
x- and y-axis, size for z-axis
Range of several cm
with accuracy less than 1m
•Three point relative alignment measurement systems (RASNIK) with accuracy ± 1μm.
Y
X
The main element used in chamber alignment
and QA/QC during chamber construction
The infrastructure - RASNIK systems
Original system used a bright dot
Lens adapted to layout
CCD camera 400000 pixels
pixel size 7x7μm2Mask and light source
Performance, in terms ofImage Position on Sensor:
x = 0.05 µm
y = 0.05 µm
scale = 2 x 10-5
RotZ = 20 µrad
Coded Mask
Y
X
RASNIK specs
Alignment information from image pattern
recognition
InfraredLED
Online Quality AssuranceTemperature variation Effect on RASNIK monitoring
for tube layer position (z coordinate)
Temperature variation at Stiffback
Temperature variation at Rasnik Tower
The height of the clean room is limited (2,65 m).
The stiffback is heated from the lights while it is suspended.
6m shift of stiffback visible!
What’s required
• RasNik components: camera, mask, lens• PC with FrameGrabber: data translation• Rasmux: a custom multiplexer
– For use with camera and mask– Suitable cables
• Software: free from NIKHEF• AUTH will contact NIKHEF for a system
or could participate in system development